The United Nations is making a desperate new push for a Syria peace conference even as the United States prepares a possible military strike, according to diplomats.
Talks on a conference are to be relaunched at the Group of 20 summit in Russia this week with the 30-month-old conflict at a new level of bitterness after the suspected use of banned chemical weapons, envoys said.
Despite doubts that the two sides in the war will come to the table, UN Under Secretary General Jeffrey Feltman discussed a possible conference during a landmark visit last week to Iran, a key backer of President Bashar al-Assad, UN officials and diplomats said.
Britain's Foreign Secretary William Hague said his government would press the Syrian opposition when Syrian National Coalition leader Ahmad al-Jarba visits London on Thursday.
He added that Prime Minister David Cameron would call on Russian President Vladimir Putin to apply pressure for such a conference when they meet in Saint Petersburg this week.
Hague on Tuesday told the British parliament there is still "an overwhelming case" to try for a negotiated settlement.
The major UN Security Council powers -- United States, Russia, China, Britain and France -- agreed a transition blueprint for Syria at a conference in Geneva in June last year. Russia and the United States agreed to push for a follow up meeting in May when the UN's Syria envoy Lakhdar Brahimi was on the verge of resigning in frustration at deadlocked peace efforts.
"There will be a lot of discussion in Saint Petersburg about making an announcement of timing for a Geneva II conference," said a senior envoy at the United Nations.
The envoy said there could be an announcement before the annual United Nations leaders' summit starting September 24 that a conference would be held, possibly in October.
The United States, Britain and France on one side and Russia and China on the other remain at odds on the Syria conflict. But they have all called for a peace conference.
"The stalemate among the key players on the council remains," Australia's UN ambassador Gary Quinlan, Security Council president for September, told reporters on Wednesday.
Quinlan, however, confirmed that "brokering" would now take place at the G20 summit, adding that even in Security Council talks on Wednesday the major powers had stressed the need for a peace conference.
"The problem of course is how to deliver that and how it can successfully be delivered quickly and again I imagine this is going to be a major topic of discussion among the key players" in Saint Petersburg.
The prospect of a military strike and Syria's divided opposition, which has demanded that Assad be kept out of any transitional government, bears heavily on the prospects for talks however.
Russia and the United States have halted contacts on a peace conference since the chemical weapons crisis erupted on August 21, according to UN diplomats.
Russia's Foreign Minister Sergei Lavrov said a US attack could "kill" hopes for a Geneva II.
But some western leaders believe there can be no conference until Assad has been punished for his alleged use of chemical weapons.
"What will be the interest of the Syrian dictator, Mr Bashar al-Assad, to negotiate as long as he believes that he can, as he repeated at the start of this week, "liquidate" -- these are his own terms, I repeat the terrible word "liquidate" -- his opposition," France's Prime Minister Jean-Marc Ayrault told a parliamentary debate on Syria on Wednesday.
UN envoy Brahimi has spent months on fruitless efforts trying to prod Assad's government and the opposition to the negotiating table. Having threatened to resign once in May, Brahimi said on Friday that he will soon hold new talks on his future with UN Secretary General Ban Ki-moon.
"The chances of brokering honest negotiations between the Syrian government and rebels remain remote," said Richard Gowan of New York University's Center on International Cooperation.
"It would be foolish, or just dishonest, to claim that Brahimi and Ban as individuals or the U.N. as an institution can overcome the political obstacles that have frustrated multiple mediators since 2011," he added.